1. Technical Field
The present invention relates to an image reading apparatus, a control method and program thereof.
2. Related Art
In the related art, as an image reading apparatus of this type, an apparatus is proposed in which a positional deviation of a lens unit with respect to a photoelectric conversion unit is detected, when the positional deviation occurs due to a difference in thermal expansion between the lens unit and the photoelectric conversion unit, correction data is selected among plural pieces of correction data which are stored in advance, on the basis of the detected deviation, and an electric signal is corrected based on the corrected data (JP-A-2010-56732). In this apparatus, the influence due to changes in temperature is reduced, the reading quality of the original document is improved, or the like, by favorably correcting unevenness of stripe shapes in the main scanning direction.
In the above described apparatus, it was possible to reduce the influence due to the change in the temperature, however, in the higher temperature, it was difficult to sufficiently reduce the influence due to the change in the temperature through correction alone. Therefore, when the temperature becomes high at the time of reading an image, limiting the operation by providing a periodic cooling time, or the like, may be considered. However, in such a manner, it is necessary to have the margin for the time and interval for the operation limitation, therefore, the time for reading the original document becomes longer.